Tube socket



Oct. 13, 1936. D R DE TAR 2,051,090

TUBE SOCKET Filed Jan. 50, 1954 [NI/EN me: amid/Z8. Re T m;

Patented Oct. 13, 1936 UNITED STATES PATENT, OFFICE TUBE SOCKET DonaldR. De Tar, Audubon. N. J., assignor to Radio Corporation of America, acorporation of Delaware My invention relates to electric plugand socketconnectors and, more particularly, to sockets for electric dischargedevices of the type having connecting pins or prongs extending from thebase thereof.

A preferred and well known type of base for electric discharge devicessuch as vacuum tubes is one having pins extending therefrom which areadapted to make contact on their sides with a socket contact member. Onediificulty encountered with the bases of this type has been that, withsockets formerly employed, the tube has a tendency to work out of thesocket. This has been true especially in cases where the tube issubjected to considerable vibration or where the tube is supported in ahorizontal position or hanging downward.

One object of my invention is to provide a socket of the above-mentionedtype which will hold a tube or the like securely in position.

A further object of my invention is to provide a vsocket of theabove-mentioned type which may be produced at a low cost.

A still further object of my invention is to provide a socket of theabove-mentioned type which cannot easily be damaged in use.

In a preferred embodiment of my invention, each socket contact memberconsists of an inverted U-shape member of resilient material having goodconductivity, and a cantilever steel spring arranged to force one leg ofsaid U-shaped member against a tube pin or prong. The said leg of theU-shaped member is so shaped that the contacting pin makes contact nearthe bottom or base of the U whereby the tube cannot readily work orshake out of contact with the socket contact members.

Other objects, features, and advantages of my invention will appear fromthe following description taken in connection with the accompanyingdrawing, in which,

Figure 1 is a side view of a socket, embodying my invention and having avacuum tube inserted therein,

Figure 2 is a fragmentary view of the socket and tube of Figure 1showing the position of a pin as it is being inserted into the socket,

Figure 3 is a view taken on the line 3-3 of Figure 1, and

Figure 4 is a perspective view on an enlarged scale of one of thecontact members shown in Figure 1.

Referring to Figure 1, a vacuum tube l of conventional constructioncomprising a base 3 having contact pins 5 extending therefrom is showninserted in position in my improved socket. The socket comprises a plateI of insulating material, suchas Micarta, having a plurality of openings.9 therein through which the tube contact pins- 5 may be inserted.

Adjacent to each opening 9 there is fastened a socket contact devicewhich consists of a substantially U-shape contact member ll of springymaterial such as phosphor bronze and a reinforcing or backup spring i3.Referring to Figure 4 where the socket contact device is shown moreclearly, it will be seen that the U-shape member ll consists of a baseportion Ha and two leg portions ill) and He, leg portion llb beingpositioned to make contact with a contact pin 5 (indicated in dottedlines) and having a slot Hi therein for providing a sharp wiping edgewith which the pin 5 makes contact. This log of the contact member isbent rather sharply near the base portion Ila so that thecontact pin 5will engage the leg at this bent portion, as shown in Figure 1, ratherthan at the outer end of the leg.

In the leg portion llc there is a portion ll which is punched out ofalignment with the main section of the leg in order to facilitatesoldering or otherwise connecting conductors to the contact member H.

The reinforcing spring l3, which is preferably made of thin sheet steelheat treated to a spring temper, has a base portion l3a and a springportion l3b bent at an angle thereto and tapering towards its end. Thefree end of the base portion l3a is provided with a short tab 19 which,together with the narrow end portion of the spring portion 43b, isutilized for centering or aligning the spring 13 with respect to thecontact member H during assembly.

Also for the purpose of alignment, the contact member H is provided withan opening 2| at the bottom of the leg portion He and with a notch 23 atthe top of the leg portion l lb.

The socket is assembled by placing the spring l3 inside the U -shapedmember H with the base portions of the spring l3 and member H in contactwith each other, and with the tab I9 and the end of the spring portionl3b engaging the opening 21 and the notch 23, respectively. The springl3 and contact member II are then riveted or otherwise suitably fastenedto the bottom of the plate I in such a position with respect to anopening 9 that the bent section of the leg portion llb is locatedunderneath a portion of the opening.

Figure 2 shows the relative positions of the socket elements and acontact pin 5 just as the pin is being inserted into the socket. Bycomparing this figure with Figure 1, it will be seen that as the pin 5is moved into position, both the contact member II and the spring I3 areforced away from the opening 9 whereby the pin 5 makes contact with thecontact member II only at the bend in the leg portion IIb. Also byreferring to Figure 3, it will be seen that the pin 5 makes contact withthe edges of the slot I5 so that there is a wiping or cleaning action onthe pin as it is moved into or out of the socket.

One of the main advantages in having the pin make contact with thecontact member II at a point near the plate I rather than at a pointnear the end of the leg portion I lb or along its entire length, is thatthe tube is held more securely in position. One reason for this is thatthe force exerted against the pin with a given spring force is increaseddue to lever action as the point of contact of the member II and the'pin5 is moved closer to the plate I. Therefore, there is less tendency forthe tube to be shaken out of the socket by vibrations such as may beencountered in shipping the apparatus. Furthermore, even if the tube isshaken part way out of the socket, its pins will still be held in goodcontact relation with the. contact members II since the contact wasoriginally being made at a point near the base end of each pin 5 ratherthan at a point near its outer end.

A still further advantage in the above described structure is that witha pin 5 making contact with a contact member II at a point near the baseof a leg portion I Ib and with the reinforcing spring I3 making contactwith the leg portion I Ib at its end, the spring I3 will hold thecontact member I I against the pin with a greater force than in the caseof conventional socket designs. That this is true will be apparent byconsidering the leg portion Ilb as a lever having its fulcrum point atthe plate I and having the force of spring I3 applied at the oppositeend of the lever; Since I the point at which force is applied to the pinis closer to the fulcrum point than to the other end of the lever, theforce applied to the leg portion I Ib by spring I3 is multiplied by thelever action when applied to the pin, and a spring I3 of mediumstifiness insures good contact.

The above-described spring arrangement also prevents possible damage tothe socket since it restores the contact leg I Ib to its originalposition in the event that the tube is inserted at such an angle in thesocket that it bends the portion IIb past its elastic limit.

Various modifications may be made in my invention without departing fromthe spirit and scope thereof and I desire, therefore, that only suchlimitations shall be placed thereon as are necessitated by the prior artand are set forth in the appended claims. I

I claim as my invention:

1. In a socket for a device having a. contact pin, a plate having anopening therein for said pin, a contact member having a base portion andan arm portion having a free end, means for fastening said base portionto said plate at a point near said opening, said arm portion extendingaway from said plate, said contact member being so positioned that saidarm portion extends over a portion of said opening, said arm portionbeing so shaped that at a point nearer said base than the free end ofsaid arm portion it extends farther over said opening than at its freeend both before and after said pin is forced into contact with said arm,and a separate auxiliary spring fastened to said plate and having a baseportion superimposed upon the base portion of said contact member and anarm portion positioned with its end in slidable contact with the end ofsaid arm portion of said contact member.

2. In a socket for a device having a contact pin, a plate having anopening therein, a contact member fastened to said plate at a point nearsaid opening, said member having a portion bent away from said platewhereby there is a bend in said portion, said bend being nearer saidplate than the end of said portion, said member being so positioned thatsaid bend extends farther over said opening than any other part of saidportion whereby a contact pin inserted into said opening makes contactwith said member at said bend, and a separate spring member fastened tosaid plate and so positioned that its free end makes. contact with andonly with the end of said por-- tion to force said bend againsta contactpin.

3. In a socket for a device having a contact pin, a plate having anopening therein, a substantially U-shaped contact member having anopening at the base of one leg of said U and having a notch in the endof the other leg of said U, a spring having abase portion and a springportion which is at an angle to said base portion, said base portionhaving a tab on the free end thereof, said spring being positionedinside said contact member with said tab in said opening and with thefree end of said spring portion in said notch, and means for fasteningsaid spring and said contact member to said plate at a point near saidopening.

DONALD R. DE TAR.

